Button to Reroll Shop Disappeared

As you can see in the screenshot, the button literally vanished.

It happend suddenly during the game. I can't say what caused it, maybe I was doing some weird mouse movements or something. This bug lasted for the entire game and left me unable to spend my gold on viewing new champions. Clicking the blank space did nothing. My only option was to buy XP and hope for good rolls. I asked the other players if they were experiencing the same bug, but they didn't have any issue with rerolling. My next game was fine again. I hope this bug gets fixed asap since it severly affects your ability to even play, let alone win a game.